(a) Field of the Invention
The present invention relates to a liquid crystal display and an apparatus and method for driving the same. More specifically, the present invention relates to a liquid crystal display capable of realizing a pre-charging method even in the random data-enable mode, and an apparatus and method for driving the same.
(b) Description of the Related Art
In general, a liquid crystal display (LCD) is a display device in which an electric field is applied to a liquid crystal layer having anisotropic dielectric constant permitivity sandwiched between two substrates, said electric field being adjusted to control the amount of light incident upon the substrates and thereby obtain a desired image. Such LCDs, including inter alia, a flat panel type display (FPD) that is very handy to carry, and a thin film transistor (TFT) LCD using a TFT as a switching element are, widely used.
Increased resolution of the LCD has lead to a rapid reduction of the pixel charging time needed. A pre-charging method as illustrated in FIG. 1 is used in order to compensate for the reduced charging time. The term “pre-charging method” as used herein refers to a method of charging a specific pixel over time that involves previously charging a corresponding pixel with data of an adjacent pixel (i.e. a pixel adjacent to the conrresponding pixel) having the same polarity as the corresponding pixel so as to invert the polarity of the pixel and thereafter charging the adjacent pixel with the data of the corresponding pixel.
A conventional gate signal usually appears every frame. However, as illustrated in FIG. 1, the typical pre-charging method compensates for the charging time in such a manner that an additional pre-charging gate pulse is used to previously charge the N-th pixel with the data of the (N−1)-th pixel having the same polarity as the N-th pixel prior to charging with the data of the N-th pixel.
More specifically, two vertical sync start signals STV have to be fed into the gate driver in order to generate a pre-charging gate pulse. For this purpose, use is made of a method of previously generating the vertical sync start signals STV at a designated position using a counter for a frame blank interval.
The data-enable (DE) mode makes the data-enable (DE) signal ‘high’ only during the interval having effective data. Driving the LCD without any problem, even with an irregular interval of the effective data, would be wanted. However, the conventional method using the counter is problematic in that it does not display an image when the interval of the effective data is irregular.
When the output interval of the effective data is irregular, i.e., in the random DE mode, the blank intervals of data-enable signals (for example, t1 and t2) are not conformable with each other, the consequence of which is failure to obtain a normal display of the LCD image.